Don't pat yourself on the back for flying on a plane that uses biofuels: If the fuel comes from palm oil grown on land converted from rainforest, it's responsible for 10 times more carbon dioxide emissions than conventional fuel, according to MIT researchers.

Massachusetts became less optimistic about biomass once it became obvious that wood-burning plants were larger versions of the ovens used in Little House on the Prairie. We can probably learn a lot about sustainable living from the Ingallses, but their heating system was maybe not the greenest.